1. Field of the Invention
The present invention relates to a piezoelectric thin film element, a manufacturing method thereof, and a liquid ejecting head and liquid ejecting apparatus employing the same, and more particularly to a piezoelectric thin film element or the like with superior piezoelectric properties and productivity.
2. Description of the Related Art
Piezoelectric thin film elements that employ piezoelectric thin films that contain crystals typified by PZT (lead zirconate titanate; Pb(ZrxTi1-x)O3) have functions such as spontaneous polarization, high permittivity, electro-optic effects, piezoelectric effects, and pyroelectric effects, and are applied in extensive device development.
A piezoelectric thin film element is structured by sequentially stacking a substrate, a diaphragm, a bottom electrode, a piezoelectric thin film, and a top electrode. Since piezoelectric properties of a piezoelectric thin film vary according to the condition of the crystal (such as the orientation of the crystal that makes up the film), the condition of the crystal must be controlled when the piezoelectric thin film is formed.
Possible methods of forming a piezoelectric thin film include sputtering, sol-gel processes, CVD, laser ablation, and the like, but sol-gel processes, which form a film by sol application, drying, pyrolyzing and annealing, are superior for controlling the condition of the crystal.
Such piezoelectric thin films are known to have superior piezoelectric properties when comprising a PZT fine crystal film with a high degree of orientation.
In conventional practice, PZT crystal films composed of stacked material comprising a plurality of thin layers have been suggested for obtaining a PZT fine crystal film.
However, using stacked material comprising a plurality of thin layers for the PZT crystal film has disadvantages in that the number of layers must be increased in order to obtain the desired thickness, increasing the number of processes for forming the layers and decreasing productivity. Due to the increase in the number or processes for forming the layers, there is also a possibility that chances will increase for contaminants such as waste to get mixed inside the film, causing the risk of reduced reliability for the piezoelectric thin film element.